Stone's point regarding our need for fire (Spirit) union leads inevitably to --

(Eph. 5:18-21 ESV) 18 And do not get drunk with wine, for that is debauchery, but be filled with the Spirit, 19 addressing one another in psalms and hymns and spiritual songs, singing and making melody to the Lord with your heart, 20 giving thanks always and for everything to God the Father in the name of our Lord Jesus Christ, 21 submitting to one another out of reverence for Christ.

Our spiritual disease, which Stone calls book, head, and water union, is amply demonstrated by the fact that, to many among us, this passage is about what it does not say. It says nothing of instrumental music, and so it's read as a prohibition against instruments. We thereby entirely miss what it does say!It says that we are to "be filled with the Spirit ... ." The references to singing are, grammatically, participles hanging on the verb "be filled." You can't get the participles right if you don't understand the verb they modify. Hence, we should not make the least attempt to apply this passage without first exegeting "be filled with the Spirit" -- as this is the central point of the passage -- and yet this is the one part of the passage the we refuse to read, teach, preach, or understand! And yet from the very founding of the Restoration Movement, Stone himself referred to being filled with the Spirit as a return to the "ancient order of things." To Stone, being filled with the Spirit is of the essence to restoring First Century Christianity. It's not about getting the Sunday morning assembly right. It's about getting the right infilling. Do that, and Paul promises us that we'll respond to the Spirit's work in us by singing, giving thanks, and submitting to each other.If your congregation is not characterized by singing, thanksgiving, and mutual submission, then you have a fire problem. You are not filled with the Spirit -- and until that happens, the rest of the passage cannot happen.Fire union is unity of the Spirit. It's the unity that we receive when we submit to God's filling with the Spirit, when we take seriously the passive voice in Eph 5:18, which says that God himself will fill us -- if we'll just let him.Believe it or not, this passage is a reference back to Jer 31 --

(Jer. 31:31-34 ESV)  31 "Behold, the days are coming, declares the LORD, when I will make a new covenant with the house of Israel and the house of Judah,  32 not like the covenant that I made with their fathers on the day when I took them by the hand to bring them out of the land of Egypt, my covenant that they broke, though I was their husband, declares the LORD.  33 For this is the covenant that I will make with the house of Israel after those days, declares the LORD: I will put my law within them, and I will write it on their hearts. And I will be their God, and they shall be my people.  34 And no longer shall each one teach his neighbor and each his brother, saying, 'Know the LORD,' for they shall all know me, from the least of them to the greatest, declares the LORD. For I will forgive their iniquity, and I will remember their sin no more."

The new covenant (or testament), Jeremiah prophesies, will result in God himself entering our hearts and minds and writing his laws on them. (The entire passage is quoted in Heb 8 to make exactly this point.) It's about the Spirit's work in us.

(Ezek. 36:26-27 ESV)  26 And I will give you a new heart, and a new spirit I will put within you. And I will remove the heart of stone from your flesh and give you a heart of flesh.  27 And I will put my Spirit within you, and cause you to walk in my statutes and be careful to obey my rules.

The prophecies all point toward the coming Spirit -- not to baptism, not to better Bible study, not to deeper hermeneutics -- but to the Spirit placed by God in our hearts and minds to change us -- transform us -- so that we become more and more like Jesus and thus more and more united.

(2 Cor. 3:17-18 ESV)  17 Now the Lord is the Spirit, and where the Spirit of the Lord is, there is freedom.  18 And we all, with unveiled face, beholding the glory of the Lord, are being transformed into the same image from one degree of glory to another. For this comes from the Lord who is the Spirit.

(Rom. 8:29 ESV)  29 For those whom he foreknew he also predestined to be conformed to the image of his Son, in order that he might be the firstborn among many brothers.

The Spirit transforms us into the image of the Lord. We become like Jesus! And as we become like Jesus, we find ourselves united -- not by our efforts but by the Spirit's work within us. If we are willing to submit to the Spirit's transforming work. If we'll let God's holy fire transform us. And if we'll recognize the transformation he is performing in others -- who, like us, are far from perfect but nonetheless seeking to be obedient to the One who also fills them with the Spirit.